1. Field of the Invention
This invention relates to recording liquid composition suitable for recording by means of writing tools or for so-called ink-jet recording process wherein said recording liquid composition is ejected from an orifice of a recording head to be flown as liquid droplets.
2. Description of the Prior Art
For carrying recording on paper or the like with writing tools (fountain pen, felt pen, etc.), there have long been used recording liquids, generally called "ink", which are solutions of various dyes in water or organic solvent.
Recording liquids of similar compositions are known to be used for the ink-jet recording process in which a recording liquid within a recording head is ejected by utilizing, for instance, oscillation of a piezo oscillator, electrostatic attraction due to a high voltage applied, or the like. However, much more strict performance characteristics are required for recording liquids used for the ink-jet recording process than for inks used for general writing tools such as fountain pens and felt pens.
The ink-jet recording process generates less noises and permits a high-speed recording and color recording on plain paper without any special fixing treatment, so that various types of ink-jet recording systems are investigated energetically.
Recording liquids for any of various types of ink-jet recording systems are demanded to fulfill the following requirements and the like:
(1) Physical properties of recording liquid such as viscosity and surface tension are each within a proper range. PA0 (2) Solutes in recording liquid have a high stability of dissolved state (hereinafter, simply referred to as "dissolution stability") and do not plug fine ejecting orifices. PA0 (3) Recording liquid gives images of sufficient optical density. PA0 (4) Recording liquid does not make a change in physical properties or deposit solid matter during storage. PA0 (5) Recording can be performed without a restriction of the type of recording member on which a record is made. PA0 (6) Recording liquid exhibits a high rate of fixing. PA0 (7) Recording liquid gives images excellent in resistance to water, solvent (particularly alcohol), light, weather, and abrasion, in degree of resolution, and in the like.
In addition to these requirements, recording liquids for the ink-jet recording process are desired to meet the following requirements:
However, images produced by conventional recording liquids, particularly by water-base recording liquids, tend to develop blotting, dislocations or scratches, or fading by water adhesion, mechanical friction, or light irradiation. In consequence, a recording liquid free from these drawbacks is looked for intensely.
Under such circumstances, a number of proposals have been made about recording liquids. Nevertheless, there has been obtained practically no recording liquid suited for actual use, in other words, meeting all the foregoing requirements.